PALLADIUM. 127 
per cent. platinum, and as malleable as the metal in ordi- 
nary use, though somewhat more hable to tarnish, owing to 
some of its impurities. Deville and Debray have perfected 
this process, and have melted over 25 pounds of platinum 
in less than three-quarters of an hour. In the process the 
osmium present is oxidized and thus removed. 
Platin-iridium. Grains of iridium have been obtained at Nischne 
Tagilsk, consisting of 76°8 iridium, and 19°64 platinum, with some 
palladium and copper. A similar platin-iridium has been obtained at 
Ava, in the East Indies. Another, from Brazil, contained 27°8 iridium, 
00°) platinum, and 6°9 of rhodium. 
LIridosmine. A compound of iridium and osmium from the platinum 
mines of Russia, South America, the Kast Indies, and California. The 
erystals are pale steel-gray hexagonal prisms; usually in fiat grains. 
H.=6°7. G.=19°5-21°1. Malleable with difficulty. 
The composition varies. One variety, called Newjanskite, contains 
iridium 46°8, osmium 493, rhodium 3:2, iron 0°7. Another, Sisser- 
skite, iridium 25°1, osmium 74°), and iridium 20, osmium 80. But 
analysis affords also from 0°5 to 12°3 of rhodium, and 02 to 6°4 
of the rarer metal rutheniwm, with traces usually of platinum, cop- 
per and iron. The grains are distinguished by their superior hardness 
from those of platinum, and also by the peculiar odor of osmium when 
heated with nitre. Iridosmine is common with the gold of Northern 
California, and injures its quality for jewelry. Occurs sparingly in 
the gold washings on the rivers Du Loup and Des Plantes, Canada. 
The metal iridium is extremely hard, and is used, as well as rho- 
dium, for points to the nibs of gold pens. Its specific gravity is 21°8. 
Laurite. Yn minute octahedrons. A ruthenium sulphide, with 3 
per cent. of osmium. From platinum sands of Borneo and Oregon. 
Palladium. 
Isometric. In minute octahedrons. Occurs mostly in 
grains, sometimes composed of divergent fibres. Color 
steel-gray, inclining to silver-white. Ductile and malleable. 
H. 4°5-5. = G.=11°3-12°2. AN 
Consists of palladium, with some platinum and iridium. 
Fuses with sulphur, but not alone. . 
Obs. Occurs in Brazil with gold, and is distinguished 
from platinum, with which it is associated, by the divergent 
structure of its grains. It was discovered by Wollaston, in 
1803. Selenpalladite, or Allopalladiwm, is native palladium 
in hexagonal tables from Tilkerode in the Hartz. It is re- 
ported also from St. Domingo and the Urals. Porpezite 
‘is palladium gold, or gold containing about 10 per cent. of 
palladium ; three samples assayed at the Rio de Janeiro 
mint yielding 11-1, 9°75, and 7:7 per cent. of palladium. 
